package day03.note;

import java.util.Random;
import java.util.Scanner;

public class txt15 {
    public static void main(String[] args) {

        Scanner s = new Scanner(System.in);
        int num=s.nextInt();//输入整数

        int i=1;//阶乘、控制次数
        int f = 1;//结果
        while (i<=num) {
            f = f * i;//累乘
            i++;//自增1
        }
        System.out.println(f);


    }
}


